The present invention relates to an apparatus and method for purifying a liquid by vaporization and subsequent condensation. As is well known to those persons familiar with the art, any liquid may be purified by vaporization in a first enclosure and subsequent recondensation in a second enclosure. Although numerous means have been devised for accomplishing the necessary changes of state, most of the known distillation systems utilize the principal of temperature variation to produce both the vaporization and the condensation. As the liquid is heated, a relatively pure vapor is formed, leaving behind any non-volatile contaminants, for example the salt in sea water. When the vapor is cooled, it condenses back into a relatively pure liquid. The principal disadvantage of these known temperature-operated systems is the large amount of energy that is required to heat the impure liquid and then cool the vapor to produce a relatively small amount of pure liquid.